Abnormal pump vibration
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There is a vertical centrifugal pump with 6 impellers, an operating speed of 975 rpm, a rated flow rate of 3400 cubic meters, and it is installed at a depth of over 20 meters below sea level. On-site issue: At low tide levels of seawater, the vibration at the drive end of this pump increases abnormally, and an alarm is even triggered; at such times, the flow rate is around 3400. At high tide, the vibration is very stable, with a flow rate of around 3600. Please, experts, help analyze the reasons
When the sea level is high, the pump operates smoothly, proving that there is nothing wrong with the pump itself； When the sea level is low, pump vibration may be caused by cavitation and an empty pump.
The level of the tide affects the net positive suction head available to the device; at low tide, this net positive suction head is lower, while that of the pump remains unchanged. Based on the phenomenon you described, cavitation should be occurring in the pump.
Cavitation can occur when the sea level is at low tide.
Vacuuming may occur during low tide levels; monitor the fluctuations in outlet pressure! Is the traffic stable!
Stable operation at the peak level indicates that there is no problem with the pump itself; be careful of cavitation and pumping vacuum issues!
Can this be understood as follows: when the sea level drops, the relative installation height of the pump increases, which leads to cavitation?
Can this be understood as follows: when the sea level drops, the relative installation height of the pump increases, which leads to cavitation?
The water pump is installed on the floating device and should function properly at low tide.
That vibration might get louder and louder. The foundation stiffness is insufficient, and its seismic resistance does not meet the requirements